Removes custom board lnker scripts

For now let's use adafruit_feather_nrf52832.

README.md

@@ -2,19 +2,20 @@
 A low power soil moisture sensor based on the nRF52840.
 
 # TODO
-* Implement ADC; check out air/water range (using protoboard)
+* Implement BLE advertising with moisture, battery level
 * Figure out how to calibrate the ADC when running from different voltages, as the battery discharges
 * Implement deep sleep
-* Implement BLE advertising with moisture, battery level
 * Measure current in deep sleep
 * Measure current in operation (ADC + BLE adversiting)
 * Test with a range of 2-5V input. Disconnect from USB and monitor using a serial post. Use the bench power supply to power Vcc with variable voltage. *DO NOT CONNECT VCC FROM THE USB-TO-SERIAL BOARD!**
 * Test with a coin cell
+* Implement ADC for battery monitoring
 * Figure out a way for people to configure the device with a custom name. Idea: BLE service (this is what my [hacked xiaomi temp sensor](https://github.com/atc1441/ATC_MiThermometer) does)
 * Figure out how OTA works (if at all) over BLE
 * Design new board using the nrf52 instead of esp32
 
 # Done
+* Implement ADC for the parasitic capacitor; check out air/water range (using protoboard)
 * Simple PWM square wave generator
 * Hook square wave generator to the protoboard sensor circuit
 * Make the protoboard sensor work

code/parasite/ldscripts/nrf52832_s132_v6.ld

@@ -1,40 +0,0 @@
-/* Linker script to configure memory regions. */
-/* Source: https://raw.githubusercontent.com/adafruit/Adafruit_nRF52_Arduino/master/cores/nRF5/linker/nrf52832_s132_v6.ld */
-
-SEARCH_DIR(.)
-GROUP(-lgcc -lc -lnosys)
-
-MEMORY
-{
-  FLASH (rx)     : ORIGIN = 0x26000, LENGTH = 0x6D000 - 0x26000
-
-  /* SRAM required by S132 depend on
-   * - Attribute Table Size
-   * - Vendor UUID count
-   * - Max ATT MTU
-   * - Concurrent connection peripheral + central + secure links
-   * - Event Len, HVN queue, Write CMD queue
-   */
-  RAM (rwx) :  ORIGIN = 0x20003600, LENGTH = 0x20010000 - 0x20003600
-}
-
-SECTIONS
-{
-  . = ALIGN(4);
-  .svc_data :
-  {
-    PROVIDE(__start_svc_data = .);
-    KEEP(*(.svc_data))
-    PROVIDE(__stop_svc_data = .);
-  } > RAM
-
-  .fs_data :
-  {
-    PROVIDE(__start_fs_data = .);
-    KEEP(*(.fs_data))
-    PROVIDE(__stop_fs_data = .);
-  } > RAM
-} INSERT AFTER .data;
-
-/* TODO(rbaron): This should be failing but it's not. Maybe it's loading it from somewhere else? */
-INCLUDE "nrf52_common.ld"

code/parasite/lib/parasite/ble.cpp

@@ -0,0 +1,5 @@
+#include "ble.h"
+
+#include "ble_advdata.h"
+#include "nrf_sdh.h"
+#include "nrf_sdh_ble.h"

code/parasite/lib/parasite/ble.h

@@ -0,0 +1,14 @@
+#ifndef _PARASITE_BLE_H_
+#define _PARASITE_BLE_H_
+
+#include <string>
+
+namespace parasite {
+
+class BLEAdvertiser {
+ public:
+  void Advertise(std::string name, double moisture) {}
+}
+
+}  // namespace parasite
+#endif  // _PARASITE_BLE_H_

code/parasite/platformio.ini

@@ -9,13 +9,14 @@
 ; https://docs.platformio.org/page/projectconf.html
 
 [common]
-check_tool = clangtidy
+lib_deps = sandeepmistry/BLEPeripheral@^0.4.0
 
 [env:e73-tbb]
 platform = nordicnrf52
 board = adafruit_feather_nrf52832
-; Additionally, I had to force use_adafruit = True in platforms/nordicnrf52/builder/main.py
-; board = e73-tbb
 framework = arduino
 build_flags = -DNRF52 -DS132 -DNRF51_S132
-board_build.ldscript = ./ldscripts/nrf52832_s132_v6.ld
+
+; Let's keep it simple for now and just use adafruit_feather_nrf52832.
+; board = e73-tbb
+; board_build.ldscript = ./ldscripts/nrf52832_s132_v6.ld

code/parasite/src/main.cpp

@@ -1,7 +1,10 @@
 #include <Arduino.h>
 
+// #include "ble.h"
 #include "pwm.h"
 
+#include "nrf_sdh_ble.h"
+
 constexpr int kLED1Pin = 17;
 constexpr int kLED2Pin = 18;
 constexpr int kPWMPin = 19;
@@ -9,6 +12,23 @@ constexpr int kSensAnalogPin = 4;  // AIN2
 constexpr int kDischargeEnablePin = 16;
 constexpr double kPWMFrequency = 500000;
 
+// static void ble_stack_init(void) {
+//   ret_code_t err_code;
+
+//   err_code = nrf_sdh_enable_request();
+//   APP_ERROR_CHECK(err_code);
+
+//   // Configure the BLE stack using the default settings.
+//   // Fetch the start address of the application RAM.
+//   uint32_t ram_start = 0;
+//   err_code = nrf_sdh_ble_default_cfg_set(APP_BLE_CONN_CFG_TAG, &ram_start);
+//   APP_ERROR_CHECK(err_code);
+
+//   // Enable BLE stack.
+//   err_code = nrf_sdh_ble_enable(&ram_start);
+//   APP_ERROR_CHECK(err_code);
+// }
+
 void setup() {
   Serial.begin(9600);
   pinMode(kLED1Pin, OUTPUT);

resources.md

@@ -140,4 +140,9 @@ I'm getting ~680 when in the air; ~65 while holding the sensor. The default reso
 # Battery monitoring
 * Good post on how to measure lipo batteries: [link](https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/measuring-lithium-battery-voltage-with-nrf52#:~:text=To%20reduce%20the%20leakage%20current,of%2040%20us%2C%20see%20here.)
 
+# BLE
+* BLE examples for platformio with nordicnrf52 platform: [link](https://github.com/platformio/platform-nordicnrf52/tree/master/examples)
+* [BLEPeripheral](https://github.com/sandeepmistry/arduino-BLEPeripheral) seems to be a popular library choice
+* [nrf5 BLE examples](https://devzone.nordicsemi.com/nordic/short-range-guides/b/bluetooth-low-energy/posts/ble-advertising-a-beginners-tutorial) are way more complicated than I need for now
+
 # OTA